The present invention improves upon the apparatus and methods of U.S. Pat. Nos. 5,107,835 and 5,109,848, both of which are incorporated by reference. The ornamental appearance of one version of practicing the present invention is described in U.S. Pat. No. D603,971, incorporated by reference.
It has long been known that the neurological system operates significantly based on electrical impulses. The neurological system works in two directions, both transmitting feeling sensation and pain to the brain, and in firing muscles responsive to impulses from the brain.
It has also long been known that non-biological sources of electrical stimulation can be used to control certain muscles. For instance, the pacemaker works on this principle. Transcutaneous electrical stimulation has also been used in a variety of devices. In most applications, the placement of the electrodes and the electrical signal applied are pre-selected based upon a desired result. The apparatus and methods of U.S. Pat. Nos. 5,107,835 and 5,109,848 operate in this way, using a particular dual periodic-exponential signal form. The periodic-exponential signal form more closely resembles the exponential character of the patient's natural signals. The dual nature of the signal form allows one periodic-exponential signal suitable for sensory stimulation, and a second period-exponential signal suitable for muscle stimulation. In the device of U.S. Pat. Nos. 5,107,835 and 5,109,848, separate rheostat controls enabled a) amplitude control over the muscle stimulation waveform; b) frequency control over primary pulse of the muscle stimulation waveform; and c) control over the “on” portion of the duty cycle of the muscle stimulation waveform. While the device and methods of U.S. Pat. Nos. 5,107,835 and 5,109,848 provided many beneficial results, they did not enable full utilization of the potential for electro-therapeutic stimulation using the dual periodic-exponential signal form. The present invention is directed to an improved electro-therapeutic stimulator for providing enhanced periodic-exponential signal forms.